SOLVED PAPER 2021 (CDS) (I) (Elementary Mathematics)

Total Questions: 100

81. The sides of a right-angled triangle are in the ratio x : (x - 1) : (x - 18). What is the perimeter of the triangle?

Correct Answer: (c) 56 units
Solution:


82. ABC is a triangle right angled at B. Let M and N be two points on AB such that AM = MN = NB Let P and Q be two points on AC such that PM is parallel to QN and QN is parallel to CB. If BC = 12cm, then what is (PM+QN) equal to?

Correct Answer: (c) 12 cm
Solution:



83. AB and CD are the diameters of a circle which intersect at P. Join AC, CB, BD and DA. If ∠PAD = 60°, then what is ∠BPD equal to?

Correct Answer: (d) 120°
Solution:

84. An equilateral triangle ABC and a scalene DBC are inscribed in a circle on same side of the arc. What is ∠BDC equal to?

Correct Answer: (c) 60°
Solution:

85. The sides of a triangle ABC are 4 cm, 6 cm and 8 cm. With the vertices of the triangle as centres, three circles are drawn each touching the other two externally. What is the sum of the radii of the three circles?

Correct Answer: (c) 9 cm
Solution:


86. Let PAB be a secant to a circle intersecting the circle at A and B. Let PT be the tangent segment. If PA = 9 cm and PT = 12cm, then what is AB equal to?

Correct Answer: (c) 7 cm
Solution:

87. If the perimeter of a right-angled triangle is 30 cm and the hypotenuse is 13 cm, then what is the area of the triangle?

Correct Answer: (c) 30 cm²
Solution:

88. ABC is a triangle right-angled at C. Let p be the length of the perpendicular drawn from C on AB. If BC = 6 cm and CA = 8cm, then what is the value of p?

Correct Answer: (c) 4.8 cm
Solution:

89. ABCD is a trapezium in which AB is parallel to DC and 2AB = 3DC. The diagonals AC and BD intersect at O. What is the ratio of the area of ΔAOB to that of ΔDOC ?

Correct Answer: (d) 9 : 4
Solution:

90. A circle touches all the four sides of a quadrilateral ABCD. If AB = 9 cm, BC = 8 cm and CD = 12 cm, then what is DA equal to?

Correct Answer: (b) 13 cm
Solution: